Interbody fusion is a surgical spinal procedure that places a porous metallic, plastic, or composite cage device and/or bone graft between adjacent vertebrae in the area usually occupied by an intervertebral disc, maintaining spinal alignment and disc height. Anterior lumbar interbody fusion (ALIF) is a spinal fusion procedure that utilizes an anterior (i.e. front) approach through the abdomen region to fuse adjacent vertebrae of the lumbar spine. Likewise, posterior lumbar interbody fusion (PLIF) is a spinal fusion procedure that utilizes a posterior (i.e. rear) approach through the back region to fuse adjacent vertebrae of the lumbar spine. 360-degree fusion and other similar procedures are a combination/variation of ALIF and PLIF. The intervertebral disc is removed using appropriate rasping and grasping tools and replaced with a cage device and/or bone graft after appropriate distraction and spacing tools are used to restore the normal height of the intervertebral space. ALIF is preferred when either one or multiple spinal levels are being fused and one or multiple intervertebral discs must be removed, and may be performed in conjunction with a posterior decompression (i.e. a laminectomy) and/or the placement of stabilizing instrumentation (i.e. screws and rods, plates, etc.). Because during ALIF the spinal nerves and other neurologic structures do not have to be retracted, wide access to the intervertebral space(s) of interest is provided without unacceptable risk of neurologic injury. ALIF is used to treat a variety of painful spinal conditions, such as spondylolisthesis and degenerative disc disease, among others. PLIF is also preferred when either one or multiple spinal levels are being fused and one or multiple intervertebral discs must be removed, and may be performed in conjunction with the placement of stabilizing instrumentation (i.e. screws and rods, plates, etc.). PLIF is also used to treat a variety of painful spinal conditions, such as spondylolisthesis and degenerative disc disease, among others. In either and all cases, it is often desirable to place an implant device laterally, that is, at an angle or substantially perpendicular to the anterior or posterior access axes, or vice versa.
Conventional cage devices typically include some sort of retention mechanism to hold them securely in the intervertebral space. Such retention mechanisms include biting and locking structures that engage the endplate(s) of the vertebral body or bodies of interest, screw assemblies that engage the vertebral body or bodies of interest, plate structures that engage the vertebral body or bodies of interest, etc. All of these cages and retention mechanisms, however, suffer from the shortcomings that they are difficult to place, difficult to deploy, and/or tend to allow the associated cage device and/or bone graft to shift over time and thus fail to adequately maintain the normal height of the intervertebral space, for example. Again, for these and other reasons, it is often desirable to place an implant device laterally, that is, at an angle or substantially perpendicular to the anterior or posterior access axes, or vice versa.